Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot

Conner, R. L., Chang, K. F., Hwang, S. F., Warkentin, T. D. and McRae, K. B. 2013. Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot. Can. J. Plant Sci. 93: 473–482. Aphanomyces root rot, caused by Aphanomyces euteiches Drechs., is a serious disease of peas (Pisum sativum) that can severely reduce seed yield, and few effective control measures are available. The development of pea cultivars with tolerance or partial resistance to Aphanomyces root rot is generally considered to be one of the best options to reduce yield loss. A 4-yr field study was conducted at disease-free sites and at an Aphanomyces root rot site to compare the responses of cultivars and lines in the presence and absence of Aphanomyces root rot, identify breeding lines with tolerance and to evaluate the effects of tolerance on plant growth, disease severity and yield. At the Aphanomyces root rot site, a second test was established in which the phosphite fungicide Phostrol™ was applied as a soil drench treatment to the pea cultivars and lines. Aphanomyces root rot reduced seedling emergence, biomass production and yield in the susceptible pea genotypes. However, line 00-2067 consistently produced relatively high yields at all the field sites. At the Aphanomyces root rot site, yield was closely associated with plant vigour and shoot weight. Small, but significant, differences (P<0.05) in disease severity were observed between susceptible cultivars and tolerant lines indicating that the lines producing high yields at the Aphanomyces root rot site are tolerant rather than partially resistant. The root/shoot weight ratio was very low in the tolerant lines, indicating that even though their root systems were reduced and severely damaged by root rot, they were still able to produce high yields under favourable conditions for the disease. Drench application of the fungicide Phostrol™ did not significantly reduce root rot severity or improve the performance of any of the pea cultivars or lines.

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Yield losses in canola in response to blackleg disease

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0259 ◽

2020 ◽

Vol 100 (5) ◽

pp. 488-494

Author(s):

Yixiao Wang ◽

Stephen E. Strelkov ◽

Sheau-Fang Hwang

Keyword(s):

Disease Severity ◽

Field Experiments ◽

Leptosphaeria Maculans ◽

Economic Benefits ◽

Control Measures ◽

Yield Losses ◽

Blackleg Disease ◽

Brassica Napus L ◽

Moderately Resistant ◽

The Relationship

Blackleg, caused by Leptosphaeria maculans (Desm.) Ces. & De Not., is an important disease of canola (Brassica napus L.) worldwide. In Canada, blackleg is managed mainly by the cultivation of resistant or moderately resistant canola hybrids. Field experiments were conducted in Edmonton, AB, Canada, in 2017 and 2018 to determine the relationship between blackleg disease severity and yield in the moderately resistant canola hybrids ‘73-15RR’ and ‘1950RR’. Blackleg severity was rated on a 0–5 scale, where 0 = no disease and 5 = plant death. Regression analysis showed that relationships between disease severity and pod number and seed yield were best explained by second-degree quadratic equations in all site-years for both cultivars. Percentage yield loss increased by 18%–99% and 26%–86% in plants of ‘73-15RR’ and ‘1950RR’, respectively, with disease severities of 2–5 compared with plants with severities of 0–1. An improved knowledge of the relationship between blackleg severity and yield losses is important for a more accurate evaluation of the agronomic efficacy and economic benefits of control measures.

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First report of Plectosphaerella cucumerina causing root rot on fennel in China

Plant Disease ◽

10.1094/pdis-01-21-0166-pdn ◽

2021 ◽

Author(s):

Fengfeng Cai ◽

Chengde Yang ◽

Ting Ma

Keyword(s):

Root Rot ◽

Morphological Characteristics ◽

Control Measures ◽

Effective Control ◽

Herbaceous Plant ◽

Conidial Suspension ◽

Foeniculum Vulgare ◽

Medicinal Uses ◽

First Report ◽

Plectosphaerella Cucumerina

Fennel (Foeniculum vulgare Mill.) is herbaceous plant commonly cultivated for culinary and medicinal uses in China (Shi et al. 2016 ). In May 2019, disease of fennel was observed in Yumen City, Gansu Province, China (N 40°28'/E 97°05'). The incidence across the fields (about 0.23 hectare) was about 4.5%. The outer leaves of diseased fennel wilted, the rhizome changed color from brown to dark brown，necrosis and rot symptoms developed on the root. Finally, the whole plant wilted and died. When pulling up, it was easy to break the root. To identify the pathogen, 15 samples of diseased plants were collected and symptomatic rhizome tissues were surface disinfected with 0.1% HgCl solution for 30 s, rinsed in sterilized water 3 times, placed on potato dextrose agar (PDA), and incubated at 25℃ in the dark. About 7 days, hyphal tips from the tissue edge were transferred to a new PDA for purification. Three isolates obtained were named as hxa, hxb and hxc. To confirm their pathogenicity, two-month old fennel seedings planted in pots, three seedings per pot, with sterilized nutrient soil were inoculated by pouring 50 ml of conidial suspension (107 conidium/mL) produced from the three isolates. Plants inoculated with sterilized water only were included as controls. Six pots of inoculated plants were maintained in climatic cabinet / chamber (> 85% RH, 25°C). The pathogenicity tests were conducted twice. After 7 days, the plants inoculated with conidial suspension of hxa developed brown necrosis and wilt symptoms resembling those originally observed in the field, whereas the controls and the plants inoculated with the other two isolates had no symptoms. Furthermore, hxa was reisolated from rhizome of these diseased plants. The results indicated that isolate hxa was the pathogen causing root rot of fennel. The colonies of hxa on PDA were white-to-cream, slimy, mycelium appressed, aerial mycelium absent. Mycelium was hyaline, septate and formed hyphal coils. Conidiophores were solitary, hyaline, sometimes crooked or sinuous, widest at the base, gradually tapering to the apex. Conidia were smooth, hyaline, aseptate, elliptical and ovoid, measuring 5.97 to 9.51 × 2.13 to 3.58 um (avg. 7.58×2.78, n=100). These morphological characters of the fungal isolates were identical to those of Plectosphaerella cucumerina (Carlucci et al. 2012). For molecular identification, genomic DNA was extracted from the mycelium, and the rDNA internal transcribed spacer (ITS) region, portions of the 28S ribosomal RNA (LSU), calmodulin (CaM) and translation elongation factor 1α (Ef‐1α) gene were amplified using primer pairs ITS1/ITS4, LROR/LR5, CMD5/CMD6 and 688f/1251R (White et al., 1990; Hopple et al., 1999; Hong et al., 2005; Alves et al., 2008), respectively. The sequences of these genes were deposited in GenBank (accessions: ITS as MW426266, LSU as MW433724, CaM as MW448071 and EF-1a as MW459981) and used in analysis to generate a phylogenetic tree. These sequences showed 100, 100, 96 and 97.32% homology to the sequences of P. cucumerina (GenBank accession no. EU594566, MH867359, KY416911 and KY964491), respectively. According to morphological characteristics and phylogenetic analysis, isolate hxa was identified as P. cucumerina. To our knowledge, this is the first report of P. cucumerina causing root rot of fennel in China as well as worldwide. This finding may help to take effective control measures of root rot on fennel.

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Assessment of yield loss caused by common root rot in wheat cultivars in Queensland

Australian Journal of Agricultural Research ◽

10.1071/ar9920043 ◽

1992 ◽

Vol 43 (1) ◽

pp. 43 ◽

Cited By ~ 16

Author(s):

GB Wildermuth ◽

RD Tinline ◽

RB McNamara

Keyword(s):

Grain Yield ◽

Disease Severity ◽

Root Rot ◽

Yield Loss ◽

Grain Weight ◽

The Other ◽

Regression Equations ◽

Yield Losses ◽

Common Root ◽

Common Root Rot

The effects of common root rot (CRR) caused by Bipolaris sorokiniana on grain yield, number of tillers, number of grains and grain weight of wheat plants were determined in four field experiments. Sites with different soil populations of B. sorokiniana were selected and inoculum of the fungus added to some plots. Disease and yield measurements were made on eight cultivars and lines differing in susceptibility to CRR. Timgalen, Songlen and Hartog were susceptible whereas Kite, 1008 C16, 141-4 and ISWYN 32 were partially resistant to CRR. Grain yield, tiller and grain number, but not grain weight decreased as disease severity increased. Diseased plants had lower tiller numbers than healthy ones and as a consequence a reduced number of grains and grain yield per plant. Five methods were compared for estimating yield loss caused by the disease. Polynomial regression equations for each cultivar between yield and disease rating of sub-crown internodes or multiple regression equations between yield and disease parameters of sub-crown internodes or tiller bases were established. A third method involved the projection of yield losses from one cultivar to other cultivars and in a fourth method yield losses were estimated from actual yields. In addition, an equation Yield loss (%) = 3 46 + 0.23 disease severity) (%) was established in one experiment and used as a fifth method in the other experiments. Yield losses estimated by methods 1 and 2 were similar and higher than those from the other methods. In areas where disease severity is high, methods 1 and 5 appear to be the most suitable for determining yield losses. Losses in a susceptible cultivar, Timgalen, varied between 13.9 and 23.9% whereas those in a partially resistant cultivar, 1008 C16, varied between 6.8 and 13.6%.

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Control measures of root rot fungal pathogens by producing resistance against twelve wheat cultivars under greenhouse in Nebraska State of USA

Pakistan Journal of Botany ◽

10.30848/pjb2019-2(38) ◽

2018 ◽

Vol 51 (2) ◽

Author(s):

Tanveer Hussain ◽

Tony Adesemoye ◽

Muhammad Ishtiaq ◽

Mewash Maqbool ◽

Azhar Azam ◽

...

Keyword(s):

Root Rot ◽

Fungal Pathogens ◽

Control Measures ◽

Wheat Cultivars

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EVALUATION OF NONIONIC SURFACTANTS FOR CONTROL OF CLUBROOT OF CABBAGE USING BAREROOT AND PLUG TRANSPLANTS OF TWO CULTIVARS

HortScience ◽

10.21273/hortsci.27.6.607b ◽

1992 ◽

Vol 27 (6) ◽

pp. 607b-607

Author(s):

W. Tietjen ◽

P.J. Nitzsche ◽

W.P. Cowgill ◽

M.H. Maletta ◽

S.A. Johnston

Keyword(s):

Brassica Oleracea ◽

Disease Severity ◽

Nonionic Surfactants ◽

Plasmodiophora Brassicae ◽

Severity Index ◽

Effective Control ◽

Disease Severity Index

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

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Characterizing the effectiveness of COVID-19 mitigation measures: A data-centric approach (Preprint)

10.2196/preprints.21321 ◽

2020 ◽

Author(s):

Lukman Olagoke ◽

Ahmet E. Topcu

Keyword(s):

Control Measure ◽

Control Measures ◽

World Health ◽

Mitigation Measures ◽

Effective Control ◽

The World ◽

Decision Making Processes ◽

And Performance ◽

Health Organization ◽

The Impact

BACKGROUND COVID-19 represents a serious threat to both national health and economic systems. To curb this pandemic, the World Health Organization (WHO) issued a series of COVID-19 public safety guidelines. Different countries around the world initiated different measures in line with the WHO guidelines to mitigate and investigate the spread of COVID-19 in their territories. OBJECTIVE The aim of this paper is to quantitatively evaluate the effectiveness of these control measures using a data-centric approach. METHODS We begin with a simple text analysis of coronavirus-related articles and show that reports on similar outbreaks in the past strongly proposed similar control measures. This reaffirms the fact that these control measures are in order. Subsequently, we propose a simple performance statistic that quantifies general performance and performance under the different measures that were initiated. A density based clustering of based on performance statistic was carried out to group countries based on performance. RESULTS The performance statistic helps evaluate quantitatively the impact of COVID-19 control measures. Countries tend show variability in performance under different control measures. The performance statistic has negative correlation with cases of death which is a useful characteristics for COVID-19 control measure performance analysis. A web-based time-line visualization that enables comparison of performances and cases across continents and subregions is presented. CONCLUSIONS The performance metric is relevant for the analysis of the impact of COVID-19 control measures. This can help caregivers and policymakers identify effective control measures and reduce cases of death due to COVID-19. The interactive web visualizer provides easily digested and quick feedback to augment decision-making processes in the COVID-19 response measures evaluation. CLINICALTRIAL Not Applicable

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Effectiveness of Epidemic Preventive Policies and Hospital Strategies in Combating COVID-19 Outbreak in Taiwan

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18073456 ◽

2021 ◽

Vol 18 (7) ◽

pp. 3456

Author(s):

Ting Wan Tan ◽

Han Ling Tan ◽

Man Na Chang ◽

Wen Shu Lin ◽

Chih Ming Chang

Keyword(s):

Mortality Rate ◽

Incidence Rate ◽

Risk Ratio ◽

Early Stage ◽

Control Measures ◽

Polymerase Chain Reaction Test ◽

Effective Control ◽

Nasopharyngeal Swab ◽

Preventive Strategies ◽

Epidemic Control

(1) Background: The implementation of effective control measures in a timely fashion is crucial to control the epidemic outbreak of COVID-19. In this study, we aimed to analyze the control measures implemented during the COVID-19 outbreak, as well as evaluating the responses and outcomes at different phases for epidemic control in Taiwan. (2) Methods: This case study reviewed responses to COVID-19 and the effectiveness of a range of control measures implemented for epidemic control in Taiwan and assessed all laboratory-confirmed cases between 11 January until 20 December 2020, inclusive of these dates. The confirmation of COVID-19 infection was defined as the positive result of a reverse-transcriptase–polymerase-chain-reaction test taken from a nasopharyngeal swab. Test results were reported by the Taiwan Centers for Disease Control. The incidence rate, mortality rate, and testing rate were compiled, and the risk ratio was provided to gain insights into the effectiveness of prevention measures. (3) Results and Discussion: This study presents retrospective data on the COVID-19 incidence rate in Taiwan, combined with the vital preventive control measures, in a timeline of the early stage of the epidemic that occurred in Taiwan. The implementation of multiple strategy control measures and the assistance of technologies to control the COVID-19 epidemic in Taiwan led to a relatively slower trend in the outbreak compared to the neighboring countries. In Taiwan, 766 confirmed patients were included, comprised of 88.1% imported cases and 7.2% local transmission cases, within the studied period. The incidence rate of COVID-19 in Taiwan during the studied period was 32 per million people, with a mortality rate of 0.3 per million people. Our analysis showed a significantly raised incidence risk ratio in the countries of interest in comparison to Taiwan during the study period; in the range of 1.9 to 947.5. The outbreak was brought under control through epidemic policies and hospital strategies implemented by the Taiwan Government. (4) Conclusion: Taiwan’s preventive strategies resulted in a drastically lower risk for Taiwan nationals of contracting COVID-19 when new pharmaceutical drug or vaccines were not yet available. The preventive strategies employed by Taiwan could serve as a guide and reference for future epidemic control strategies.

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Molecular Identification of Mushroom Species in Italy: An Ongoing Project Aimed at Reinforcing the Control Measures of an Increasingly Appreciated Sustainable Food

Sustainability ◽

10.3390/su13010238 ◽

2020 ◽

Vol 13 (1) ◽

pp. 238

Author(s):

Alice Giusti ◽

Enrica Ricci ◽

Laura Gasperetti ◽

Marta Galgani ◽

Luca Polidori ◽

...

Keyword(s):

Selection Process ◽

Winning Strategy ◽

Control Measures ◽

Effective Control ◽

Mushroom Poisoning ◽

Clinical Samples ◽

Similar Species ◽

Mushroom Species ◽

Ongoing Research ◽

Genotypic Analysis

Proper investment in mushroom production (farming and wild mushroom picking activities) may represent a winning strategy for many countries, including Italy, to better face the problems of food security and environmental impact, and to break away from imports, enhancing the local products. However, the risk related to the consumption of poisoning species requires governments to implement or reinforce effective control measures to protect consumers. Mushroom identification by phenotype observation is hardly applicable if morphologically-similar species, non-whole specimens, or clinical samples are involved. Genotypic analysis is a valid alternative. An ongoing research project involving the Experimental Zooprophylactic Institute of Lazio and Tuscany, the regional Mycological Inspectorate, the Tuscany Mycological Groups Association, and the Department of Veterinary Sciences of the University of Pisa aims to reinforce the collaboration among institutions for the management of mushroom poisoning. The core’s project aims to develop an internal genetic database to support the identification of wild and cultivated mushroom species in the Italian territory. The database will include Internal Transcribed Spacer (ITS) sequences retrieved from official databases (the NCBI GenBank and the BOLD system) which are considered to be reliable, after a proper selection process, and sequences from specimens collected directly and identified by expert mycologists. Once it is validated, the database will be available and further implementable by the official network of national laboratories.

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Timing and Route of Contamination of Patient Rooms With Healthcare-Associated Pathogens

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.1066 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s412-s412

Author(s):

Sarah Redmond ◽

Jennifer Cadnum ◽

Basya Pearlmutter ◽

Natalia Pinto Herrera ◽

Curtis Donskey

Keyword(s):

Acute Care Hospital ◽

Current Control ◽

Pathogen Transmission ◽

Control Measures ◽

Effective Control ◽

Portable Devices ◽

Care Hospital ◽

Spa Typing ◽

Persistent Problem ◽

Healthcare Associated

Background: Transmission of healthcare-associated pathogens such as Clostridioides difficile and methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in healthcare facilities despite current control measures. A better understanding of the routes of pathogen transmission is needed to develop effective control measures. Methods: We conducted an observational cohort study in an acute-care hospital to identify the timing and route of transfer of pathogens to rooms of newly admitted patients with negative MRSA nares results and no known carriage of other healthcare-associated pathogens. Rooms were thoroughly cleaned and disinfected prior to patient admission. Interactions of patients with personnel and portable equipment were observed, and serial cultures for pathogens were collected from the skin of patients and from surfaces, including those observed to come in contact with personnel and equipment. For MRSA, spa typing was used to determine relatedness of patient and environmental isolates. Results: For the 17 patients enrolled, 1 or more environmental cultures became positive for MRSA in rooms of 10 patients (59%), for C. difficile in rooms of 2 patients (12%) and for vancomycin-resistant enterococci (VRE) in rooms of 2 patients (12%). The patients interacted with an average of 2.4 personnel and 0.6 portable devices per hour of observation. As shown in Figure 1, MRSA contamination of the floor occurred rapidly as personnel entered the room. In a subset of patients, MRSA was subsequently recovered from patients’ socks and bedding and ultimately from the high-touch surfaces in the room (tray table, call button, bedrail). For several patients, MRSA isolates recovered from the floor had the same spa type as isolates subsequently recovered from other sites (eg, socks, bedding, and/or high touch surfaces). The direct transfer of healthcare-associated pathogens from personnel or equipment to high-touch surfaces was not detected. Conclusions: Healthcare-associated pathogens rapidly accumulate on the floor of patient rooms and can be transferred to the socks and bedding of patients and to high-touch surfaces. Healthcare facility floors may be an underappreciated source of pathogen dissemination not addressed by current infection control measures.Funding: NoneDisclosures: None

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Genome sequence, transcriptome, and annotation of rodent malaria parasite Plasmodium yoelii nigeriensis N67

BMC Genomics ◽

10.1186/s12864-021-07555-9 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Cui Zhang ◽

Cihan Oguz ◽

Sue Huse ◽

Lu Xia ◽

Jian Wu ◽

...

Keyword(s):

Dna Sequences ◽

Malaria Parasite ◽

Vaccine Development ◽

De Novo ◽

Gene Families ◽

Plasmodium Yoelii ◽

Control Measures ◽

Effective Control ◽

Malaria Parasites ◽

Rodent Malaria

Abstract Background Rodent malaria parasites are important models for studying host-malaria parasite interactions such as host immune response, mechanisms of parasite evasion of host killing, and vaccine development. One of the rodent malaria parasites is Plasmodium yoelii, and multiple P. yoelii strains or subspecies that cause different disease phenotypes have been widely employed in various studies. The genomes and transcriptomes of several P. yoelii strains have been analyzed and annotated, including the lethal strains of P. y. yoelii YM (or 17XL) and non-lethal strains of P. y. yoelii 17XNL/17X. Genomic DNA sequences and cDNA reads from another subspecies P. y. nigeriensis N67 have been reported for studies of genetic polymorphisms and parasite response to drugs, but its genome has not been assembled and annotated. Results We performed genome sequencing of the N67 parasite using the PacBio long-read sequencing technology, de novo assembled its genome and transcriptome, and predicted 5383 genes with high overall annotation quality. Comparison of the annotated genome of the N67 parasite with those of YM and 17X parasites revealed a set of genes with N67-specific orthology, expansion of gene families, particularly the homologs of the Plasmodium chabaudi erythrocyte membrane antigen, large numbers of SNPs and indels, and proteins predicted to interact with host immune responses based on their functional domains. Conclusions The genomes of N67 and 17X parasites are highly diverse, having approximately one polymorphic site per 50 base pairs of DNA. The annotated N67 genome and transcriptome provide searchable databases for fast retrieval of genes and proteins, which will greatly facilitate our efforts in studying the parasite biology and gene function and in developing effective control measures against malaria.

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